53 Pa.C.S. § 8427: Notice of basis of underpayment.

A local taxing authority shall notify the taxpayer in writing of the basis for any underpayment that the local taxing authority has determined to exist. The notification shall include:

(1) The tax period or periods for which the underpayment is asserted.

(2) The amount of the underpayment detailed by tax period.

(3) The legal basis upon which the local taxing authority has relied to determine that an underpayment exists.

(4) An itemization of the revisions made by the local taxing authority to a return or report filed by the taxpayer that results in the determination that an underpayment exists.